The present invention relates to a conveyor system for transporting items between specified locations generally within the confines of a building over a specified path. Particularly, the present invention relates to a conveyor system for transporting items of manufacture between various assembly and work locations within a manufacturing and finishing plant. More particularly, the present invention relates to a conveyor system including individual work carrying carts that travel along a guide track that are selectively storable along the guide track at specified locations, and are completely removable from the guide track by the operator, if desired. The individual carts also have a platform that is adjustable in height for carrying the items.
Conveyors for transporting items of manufacture between different work stations are generally known. Two such conveyor systems are disclosed in U.S. Pat. Nos. 2,317,675 and 2,640,607 to DeBurgh. The known conveyor systems of this type have generally been elevated systems with substantially all of the components located above the floor. The systems include a continuously driven chain located within a continuous track, and individual carts that are moved along the track by the drive chain. The conveyor systems generally have a provision to store one or more carts in a storage position along the continuous track (close pack position).
One problem with the known conveyor systems is that because substantially all of the components for the system are located above the floor level, the floor and adjacent areas are highly obstructed.
Another problem with the known conveyor systems is that the carts or pallets are equipped with fixed drive rods (pallet pins) that extend vertically downward from the cart or pallet to engage the continuous drive chain. In order to allow the carts to remain stationary in the storage position, the drive chain must drop away from the drive rods attached to the carts. The track drops, or verticals, greatly increase the complexity of the drive chain apparatus, which in turn increases the cost of the entire system and are difficult to reposition.
Another problem with the known conveyor systems is that the carts or pallets are very difficult to remove from the track. In fact, in most of the known systems, the carts are generally not removable from the guide track under normal conditions. This greatly restricts the flexibility of the known conveyor systems.
Another problem with the known conveyor systems is that the individual carts or pallets have a product surface that is a fixed distance above the floor. This also greatly restricts the flexibility of the system because it makes the system more difficult to use for items with varying heights.
It is an object of the present invention to provide a conveyor system that has a minimum number of obstructions on the floor.
It is another object of the present invention to provide a conveyor system having a monoplane driving mechanism that remains substantially parallel to the path of movement of the conveyor carts and yet allows the carts to be disengaged from the drive mechanism at selected locations.
Yet another object of the present invention is to provide a conveyor system with carts that are easily removable from the conveyor track, at any point except storage locations along the track, when desired.
Yet another object of the present invention is to provide a conveyor system with carts that have an adjustable height platform, with the height adjustment being easily accomplished.
According to the present invention, an endless conveyor system is provided that includes individual floor supported carts that are adapted to roll along the path of a guide track. The guide track includes an endless drive means disposed within the guide track below the floor. Each individual cart includes a retractable guide means that moves between a retracted position and an extended position for engaging the guide track to guide the cart along the guide track. Each individual cart also includes a retractable engaging means that moves between a retracted position and an extended position for engaging the drive means to move the cart along the guide track. The conveyor system includes means for retracting the engaging means to stop the cart along the guide track. The conveyor system also includes means for retracting the guide means to allow the cart to be removed from the guide track.
Further, according to the present invention, the individual carts have an upper platform that includes leg means. The carts also have a lower frame with an upper surface and first support means that cooperate with the key means to support the platform at a first distance above the upper surface of the lower frame. The carts also have second support means that cooperate with the leg means to support the platform a second distance above the upper surface of the lower frame.
In preferred embodiments of the present invention, the engaging means is a retractable drive pin assembly that includes a drive pin that is spring biased to the extended position and a drive cam roller attached to the drive pin. The drive cam roller cooperates with an inclined drive cam mounted adjacent the guide track to force the pusher pin to the retracted position. One feature of the foregoing structure is that because the drive pin is retractable, the drive means can be monoplane (parallel to the floor), and the drive means can still be disengaged from the drive pin as desired. One advantage of this feature is that the drive means is much simpler to construct, and is less complicated, which increases its reliability. Another feature of the foregoing structure is that the drive pin is easily disengageable from the drive means at selected positions along the guide track. The selected positions can be changed to meet new requirements merely by relocating the drive cams. One advantage of this feature is that the cart is easily removable from the guide track after the drive pin is forced to the retracted position, if the guide means is also disengaged from the guide track.
Also in preferred embodiments of the present invention, the guide means is a retractable guide pin assembly that includes a guide pin that is spring biased to the extended position and a guide cam roller attached to the guide pin. Also included in the guide pin assembly is a retaining means to adequately retain the guide pin in the retracted position. The guide cam roller cooperates with an inclined guide cam mounted adjacent the guide track to force the guide pin to the retracted position. The retaining means then keeps the guide pin in the retracted position unless the retaining means is disengaged. One feature of the foregoing structure is that the guide pin is easily disengageable from the guide track at selected positions along the guide track. The selected positions can be changed to meet new requirements merely by relocating the guide cams. One advantage of this feature is that the cart can be reoriented in relation to the guide track when the guide pin is retracted. This allows the carts to be stacked together in the minimum required space along the guide track. The carts can also be removed from the guide track easily if both the guide pin and the drive pin are retracted.
Also in preferred embodiments of the present invention, operator activated, manual retracting means is provided to manually retract both the guide pin and the drive pin. One feature of the foregoing structure is that the guide pin and the drive pin can be simultaneously retracted by the operator by simply depressing the manual retracting means. One advantage of this feature is that the cart can be easily removed from the guide track by the operator at any position other than the storage locations (close pack) along the guide track at the choosing of the operator.
Also in preferred embodiments of the present invention, the first support means on the lower frame of the cart includes four mounting pins and the leg means on the upper platform includes four tubular legs. The second support means includes a portion of the lower frame formed to include four holes. One feature of the foregoing structure is that when the upper platform is in one orientation, the mounting pins cooperate with the tubular legs to support the upper platform a first distance above the lower frame. When the upper platform is in a second orientation, the four holes receive the four legs so that the lower frame itself supports the upper platform. Thus the upper platform has two working levels. One advantage of this feature is that the carts are adaptable to carry different sized items at the proper working level. This eliminates the need for different carts for differently sized items, thereby lowering the overall cost of the conveyor system.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of a preferred embodiment exemplifying the best mode of carrying out the invention as presently perceived. The detailed description particularly refers to the accompanying figures in which: